Modification of stereoregular polyolefins with polyethylene glycol



pending application Ser. No. 113,972,

heat sensitivity,

.tional dryer. As is United States Patent 3,366,710 MODIFICATION OF STEREOREGULAR POLY- OLEFINS WITH POLYETHYLENE GLYCOL .l'ack J. Press, 12-18 E. 'Laurelton Parkway, Teaneck, NJ. 07666 No Drawing. Continuation-impart of application Ser. No.

113,972, Apr. 4, 1961. This application Sept. 30, 1964, Ser. No. 400,611

1 Claim. (Cl. 260-896) ABSTRACT OF THE DISCLOSURE A dye receptive stereoregular polyolefin composition is prepared by using about 2 to 20 percent polyethylene glycol of molecular weight from 100,000 to 5,000,000 meltdispersed in stereoregular polypropylene, polymethylpentens, or polymethylbutene.

The invention described herein may be manufactured and used by or for the Government of the United States of America for governmental purposes without the payment of any royalties thereon or therefor.

This application is a continuation-in-part of my cofiled Apr. 4, 1961, now abandoned.

The invention relates to stereoregular polyolefins. More particularly, this invention relates to polymeric compositions having improved afiinity for dyes, said com-positions containing a major amount of stereoregular polyolefins.

, It'is known that polyethylene is vastly unsuitable for the production of textile fibers due to the relatively poor properties imparted to the product. For one thing, a staple polyethylene fiber will not hold a crimp and this is necessary for textile processing. For another, it is useless to vmake a textured or stretched yarn from a continuous polyethylene filament because the characteristics imparted to the yarn are not maintained during weaving, dyeing, or ordinary use. Further, the material from which a fabric is made must be thermally stable before it may be subjected to ordinary use. It must not have a relatively low melting point, and the final fabric must not have a high degree of nor relatively soft mechanical properties at elevated temperatures. However, the thermal properties of a polyethylene fabric are such that it is impossible to subject it to ordinary ironing without physically damaging the fabric and it has been found to shrink in the convenapparent from the foregoing, polyethylene cannot be utilized in the manufacture of everyday fabrics for ordinary use.

In recent times, it has been found that certain linear crystalline hydrocarbon polymers containing stereoregular macromolecules and having melting points between 150 and 300 C. can be used for the production of textile fibers without the inherent difficulties encountered with the use of polyethylene polymers for this purpose. Aside from melting point differences, polypropylene with a tertiary carbon and a methyl side chain, crystallizes differently and has a much higher resilience and elasticity. These properties are essential in generally useful textile fiber. Further, polymers of olefinic hydrocarbons containing stereoregular macromolecules, such as polypropylene, polymethylpentene, and polymethylbutene, offer considerable advantages in the production of fibers, particularly because of their good mechanical properties and lightweight. However, such polymers have not been satisfactory because of their poor afiinity for dyes, this poor afiinity being due to the particular chemical nature of such polyolefinic hydrocarbons.

Many processes have been proposed in order to improve the aflinity of such polyolefinic hydrocarbons for dyes, such as the addition of soluble solid substances to the molten polyolefin before spinning. The addition of basic substances facilitates dyeing with acid dyes, whereas the addition of acid substances favors dyeing with basic dyes. However, such processes have not been completely satisfactory because soluble modifiers interfere with crystallization,'impair strength and thermal stability, and are not sufliciently available in the amorphous regions where dyeing takes place.

It has also been proposed to increase the aflinity of dyes for polyolefin fibres by grafting monomers onto the fibres after subjecting the fibres to a preliminary peroxidation or to high energy radiation. When such processesare applied to the polyolefin after it is in filamentary form the surface properties of the grafted fibers are considerably modified and the dye receptivity is improved. However, when such processes are applied to highly crystalline filaments, any grafting onto the preformed fibres takes place only at the surface. Therefore, subsequent dyeing is limited to the surface portion of the fibre andthe dye does not penetrate inside the fibre.

It is therefore an object of thisinvention to provide a polymeric composition having improved aflinity for dyes devoid of all the difficulties of the prior art.

This invention relates to stereoregular polyolefins having increased affinity for dyes and other polar substances comprising a matrix of a stereoregular polyolefin taken from the group consisting of polypropylene, polymethylpentene and polymethylbutene, said matrix of polyolefin having dispersed therein between about 2 and 20% of a modifying polymer which is hydrophilic, non-soluble in the polyolefin and fusible at a temperature not exceeding the temperature of processing of the polyolefin C. to 350 C.), said modifying polymer being selected from the group consisting of alkylene oxide polymers having molecular weights between 100,000 and 5,000,000,

poly N-vinyl pyrrolidone, poly N-vinyl morpholine, and t v. poly N-vinyl oxazolidinone.

ethylene glycol resins, of different molecular weight, was prepared and labeled as follows:

M01. weight Solvent 1a 4, 000 707 lso r0 anol30 water. 1b 20,000 "Do? U I 1c 300, 000 Dloxane.

(1A) A separate sample of the above glycol resin which had a; molecular weight of 1,000,000 was labeled 1d. This sample was in powdered form.

(2) 2.5 cc. of each of the above solutions was uniformly mixed with separate gram samples of a finely powdered (50-200 mesh) commercial, uninhibited isotactic polypropylene (molecular weight about 350,000; melting point about 170 C.; melt index of about 3 and isotacticity of 95%). However, in the case of sample 1d, the resin was added in powdered form to the polypropylene.

(3) The above mixtures were then air dried (to remove most of the solvent) and then heated in a drying oven at 80 C. until all of the solvent had been removed.

(4) Each of the dried mixtures was prepared in the form of a disc in the following manner. The powder of each sample was spread uniformly in a circular shouldered Pyrex glass dish with an inside diameter of 4 inches. The dishes were then covered by an inner nesting circular shouldered Pyrex glass dish with a bottom outer separation rib projecting downwardly about 0.05 inch. The assembly weighted with a preheated 5 pound weight was then placed in an oven at 250 C. for 6 to minutes. Then the Weight was removed and the assembly was placed in a refrigerator at about 4 C. to cool. The assembly dishes were then separated to give a fused disc.

(5) A portion of each of the fusion discs after water rinsing were individually placed in a separate dye pot together with times its weight of distilled water and from 0.5 to 2% of the dye on the weight of the sample. The following dyes were utilized in separate baths viz.

AMRColour Index, Acid Red 182;

AR-Colour Index, Acid Red 127;

ASC-Cibalan Brilliant Scarlet RL, a neutral dyeing metallized acid dye;

BBColour Index, Basic Blue 26;

DO-Colour Index, Disperse Orange 3; and

DVColour Index, Disperse Violet l.

Sample Depth of Shade Undyed.

Tint.

Light. Light/medium. Medium;

Alkylene oxide polymers of 1000 to 10,000 molecular weight are considered suitable for use in plasticizing or improving the impact resistance of polypropylene. However, if these liquid or waxy substances plasticize polypropylene, they will adversely aifect the desirable properties in films and fibers. As shown, these relatively low molecular weight polyglycols have negligible effect on the dyeability of polypropylene. However, the polyalkylene oxides having molecular Weights of 100,000 to 4,00%- -000 can be used in relatively low percentages with negli gible eifect on desired physical properties to impart a greater degree of dyeability to the polypropylene as indicated by the results above.

As a follow-up to the above tests, varying percentages of polyethylene glycol resin having a molecular weight of 300,000 were utilized to form discs as set forth above in combination with the isotactic poly-propylene described. The discs were then dyed with the enumerated dyes and were judged for depth. The results of this examination are set forth below in Table 2:

dNatel:i vl=very light; l=light; lm=light to medium; m=medium;

As may be seen from the above results, the depth of coloration increased as the percentage of modifier was increased in the disc.

Example 2 DEPTH OF SHADE Disc AMR AR ASC Undyed Undyed" Undied '1" Tint Tint.

Very light.-. Light. Light.

ight Medium--. Mediu Electrical Resistivity (Xl0 ohms per square) Disc Before Dyeing After Dyeing As is apparent, with increasing molecular weight, the discs exhibited improved dyeability and reduced static propensity.

Discs prepared in accordance with the procedure outlined in Example 1, utilizing as modifier various concentrations of polyvinyl pyrrolidone, were cut radially into 6 equal sections and refused. The latter procedure was performed 4 times to give discs with fair uniformity of dispersion and similar dyeability. The discs, each of which contained varying amouts of polyvinyl pyrrolidone, were then dyed in accordance with the procedure set forth in Example 1 and the depth of shade, for each disc, was judged and set forth below:

' DEPTH OE SHADE containing varying percentages of polyvinylpyrrolidone, m.w.

Asv is apparent from the results above, the depth of coloration of each of the discs increases with the presence of increasing amounts of pyrrolidone.

Example 3 In accordance with the general procedure set forth in Example 1, I prepared two separate discs utilizing as modifiers poly N-vinyl oxazolidinone and poly N-vinyl morpholine. The dispersion of each of the homopolymers in each of their respective polypropylene discs was considered fair. Each disc exhibited only a slight increase in opacity over a control. The discs prepared with each of the modifiers was dyed in accordance with the procedure outlined in Example 1. I found that each disc was dyed to a light/ medium shade with DO disperse dyes heretofore described.

Many alternate methods of combining my modifiers with polyolefins are readily available. They may be combined during formation of the polymeric modifier or during actual polymerization of the polyolefin, with or without melting. They may be added to freshly polymerized polyolefin, which is still in solution in a suitable solvent, in the powdered form, or as a solution in a compatible solvent, or merely as a dispersion. They may be added to the polyolefin during precipitation, washing, neutralizing or compounding of the freshly prepared polyolefin prior to drying. This may be accomplished by adding the modifier as a powder or as a solution which is a non-solvent for the polyolefin.

The modifiers may also be melt mixed during processing or blending of the polymer prior to use in extension of fiber, film, coating or plastic. It may also be added as a liquid or powder to finely ground or micronized polyolefin polymers and then melt dispersed in situ during hot dip or spray coating or during spreading and heat coating operation. They may be incorporated in polyolefin solutions or emulsion and then applied to surfaces with or without heating.

The level of addition of the modifiers heretofore listed should be between 2 and 20% of the weight of the overall composition. If less than 2% is utilized, significant improvement will not be achieved in dyeability. If an amount greater than 20% is added to the polyolefin, many of the physical properties of the final product, such as fiber or film, are adversely affected. These include loss of strength and a lower resistance to repeated flexing.

Prior efforts to develop polymeric modifiers for high melting polyolefins have stressed development and use of specific polymers with relatively high solubility in the polyolefin. These modifiers included polyimines and polyvinylpyridines.

Polyimines have high molecular mobility which apparently gives them some ease of solution in polyolefins. However, there is also a high tendency to sweat out and separate when the combination is made into fiber or film. On the other hand, soluble polyvinylpyridines confer little or no dyeability on the polyolefin when dissolved therein. This appears to be the case until the preformed modified polyolefin is post treated with epoxy compounds, concentrated acids, alkylating agents, nitrous oxide gas, and alkylene oxides. However, such post treatments are diflicult, costly and generally impractical.

Under the present concept, I prefer hydrophilic polymeric modifiers which may be soluble in either water or an oxygenated solvent but which are not soluble in the polyolefin. I do prefer modifiers which are fusible and can be dispersed in the'polyolefin.

Prior experience with comparatively. less hydrophobic fiber forming polymers, such as polyacrylonitrile polymers and polyamides, have shown that the use of hydrophilic, water soluble or dispersible, modifiers is impractical. Mainly, because excessive amount of the modifier are leached out in scouring and dyeing processes. Surprisingly, I have found that my hydrophilic polymeric modifiers, when melt dispersed in the more hydrophobic polyolefin, have good dispersion stability and are not susceptible to leachage.

I have found that at comparatively low levels of addition, my modifiers confer good dyeability on the polyolefin without the necessity for costly and sometimes impractical post treatments.

My hydrophilic modifiers must be fusible with the polyolefin. This is necessary for the formation of a continuous network of modifier throughout the polyolefin in order to permit dye penetration and efficient coordination of the dye and modifier throughout the film or fibre.

The use of a non-fusible cross-linked modifier, which results in poor dispersion, is ineffectual. The required modifier network in such a case cannot be formed and the discrete, separate particles are surrounded by unmodified areas within the polyolefin matrix. As a result, dyeing is limited to the fiber surface and the dye cannot penetrate into the interior of the fiber where it is most desired.

It is generally recognized that dyeing takes place almost entirely in the more open and readily accessible amorphous areas. When a soluble modifier is utilized, it is usually spread throughout the amorphous and crystalline areas of the polyolefin. As a result, the modifier in the crystalline areas is not available for improvement in dyeability. It also interferes with crystallization and adversely affects strength and thermal stability. However, my nonsoluble, hydrophilic, polymeric modifiers are not sufficiently compatible to be a part of the more uniform and denser crystalline areas. It appears to concentrate in the more amorphous areas where it is necessary for dyeability. It has also been found that an increase in molecular weight of my modifiers, further reduces compatibility with stereoregular polyolefins and promotes concentration of the modifier in the more amorphous regions where it may improve the dyeability of the polyolefinic matrix.

Obviously, many modifications and variations of the present invention are possible in the light of the above teaching. For instance, the modifiers of this invention may be used to increase the increase opacity and the affinity of the polyolefin for finishes. They may also be used to improve the printability of the polyolefin, increase the adhesion of the polyolefin to other materials, or to reduce the overall static propensity of the =final product. It is therefore to be understood that within the scope of the appended claim, the invention may be practiced otherwise than as specifically described.

I claim:

1. A polymeric composition having improved aflinity for dyes consisting essentially of:

a matrix of stereoregular polyolefin taken from the group consisting of polypropylene, polymethylpentene, and polymethylbutene;

said matrix having melt-dispersed therein polyethylene glycol of a molecular weight from 100,000 to 5,000,- 000 in an amount between 2 and 20 percent by Weight of the combination of matrix plus polyethylene glycol as a continuous network throughout the matrix.

(References on following page) References Cited FOREIGN PATENTS UNITED STATES PATENTS 814,582 5/ 1959 GreatBrita1n. 12 1957 cappuccio et 1 76O 897 834,160 5/1960 Great Bntam.

6/1966 wanes -8 5 MURRAY TILLMAN, Primary Examiner. 6/1964 Fior et a1. 260897 10/1964 Giustiniani et a1 260-897 SAMUEL BLECH Examme" 2/ 1967 Joyner et a1. D. I. BREZNER, Assistant Examiner. 

